JP6366016B2 - Power receiving apparatus, power receiving method, and power transmission system - Google Patents

Description

  The present invention relates to a power receiving device, a power receiving method, and a power transmission system that receive power transmitted from a power transmitting device in a contactless manner.

  2. Description of the Related Art Conventionally, a contactless charging (power feeding) system that charges a power receiving device by transmitting power from a primary power transmitting device to a secondary power receiving device in a contactless manner is known. For example, the power transmission device is provided with a primary coil for power transmission, and the power reception device is provided with a secondary coil for power reception, and it is detected that the power reception device is placed on a predetermined placement surface of the power transmission device. Then, power is transmitted from the primary coil to the secondary coil in a non-contact manner, and power is induced in the secondary coil. A rechargeable battery built in the power receiving apparatus is charged by this power.

  Here, for example, a non-contact charging apparatus disclosed in Patent Document 1 is known as a prior art that secures a charging time while suppressing an influence on communication of an electronic key system in relation to the above-described non-contact charging.

  In Patent Document 1, a vehicle is provided with a non-contact charging device and an in-vehicle device, and the in-vehicle device permits engine start through mutual communication with an electronic key possessed by a user. A non-contact charging device charges a portable terminal carried by a user in a non-contact manner. The in-vehicle device generates a wake signal for detecting whether or not the electronic key is taken out of the vehicle, and transmits a signal obtained by modulating the wake signal into the vehicle. For example, when the electronic key is not in the vehicle (in other words, the electronic key is taken out of the vehicle), the ACK signal is not responded to the modulated wake signal, so the in-vehicle device generates the wake signal after a certain period of time. Then, the modulation signal of the wake signal is transmitted again. Such retransmission of the modulated signal of the wake signal is performed a plurality of times.

JP 2013-172473 A

  In the case of conventional non-contact charging including Patent Document 1 described above, when the distance between the power transmission coil in the primary side power transmission device and the power reception coil in the secondary side power reception device is short (for example, about several [mm]) ), Since the impedance change in the primary power transmission device is large, the primary power transmission device may detect that the secondary power reception device is placed on the placement surface of the power transmission device. it can.

  However, when the distance between the power transmission coil in the primary power transmission apparatus and the power reception coil in the secondary power reception apparatus is long (for example, about several tens [mm]), the impedance of the primary power transmission apparatus Since the change is small, there is a problem that the primary-side power transmission device cannot detect that the secondary-side power reception device is placed on the placement surface of the power transmission device.

  In order to solve the above-described conventional problems, the present invention increases a change in impedance in a power transmission device by causing a constant current to flow for a certain period of time when the power transmission device is approached, and is mounted on a mounting surface of the power transmission device. It is an object of the present invention to provide a power receiving device, a power receiving method, and a power transmission system for recognizing the installation.

The present invention includes a power receiving coil for receiving a non-contact power from the power transmission device, intermittent induced voltage corresponding to the intermittent power transmission power received by the power receiving coil according to the transmission current in the power transmitting device to a predetermined value A first timer circuit that counts a first predetermined time when the time is exceeded, and the power transmission according to an operation control signal from the first timer circuit while the first timer circuit counts the first predetermined time. impedance of the device is predetermined constant current to flow so as to decrease, and a constant current circuit that stops the constant current operation so that the impedance of the power transmission device and the first predetermined time has elapsed increases, at the receiving device is there.

Further, the present invention provides a power receiving method in the power receiving device, step a, the intermittent, which is powered by said power receiving coil for receiving the power receiving coil in a non-contact intermittent transmission power according to the intermittent power transmission current from the power transmission apparatus When the induced voltage corresponding to the transmitted power exceeds a predetermined value, the first timer circuit counts the first predetermined time, and the first timer circuit counts the first predetermined time while the first timer circuit counts the first predetermined time. In accordance with an operation control signal from the timer circuit, a step in which a predetermined constant current flows in the constant current circuit so that the impedance of the power transmission device decreases, and the impedance of the power transmission device increases after the first predetermined time has elapsed. And stopping the operation of the constant current circuit .

  In addition, the present invention is a power transmission system including a power transmission device and a power reception device, wherein the power transmission device transmits power corresponding to an intermittent power transmission current in a contactless manner, and the power reception device is a predetermined power transmission system. And a power receiving coil that receives power transmitted from the power transmitting coil, and the power receiving coil receives power from the power receiving coil. A first timer circuit for measuring a first predetermined time when an induced voltage corresponding to electric power exceeds a predetermined value; and while the first timer circuit measures the first predetermined time, from the first timer circuit A constant current circuit through which a predetermined constant current flows according to the operation control signal, wherein the position detection unit is configured to change the impedance of the power transmission device based on the predetermined constant current. Is the predetermined It detects that it has been placed on the surface, a power transmission system.

  According to the present invention, when approaching the power transmission device, a constant current is allowed to flow for a certain period of time to increase the impedance change in the power transmission device and to recognize that the power transmission device is placed on the placement surface of the power transmission device. it can.

The block diagram which shows an example of the system configuration | structure of the electric power transmission system of this embodiment (A) The figure which shows an example of the connection relation of two timer circuits TM1 and TM2, a constant current circuit, and DC / DC of a power receiving apparatus, (B) Explanatory drawing of the mounting detection area and foreign material detection area in a power transmission apparatus (A) An explanatory view showing an example of operation while the timer circuit TM1 measures the first predetermined time Td1, (B) after the timer circuit TM1 finishes counting the first predetermined time Td1, and the timer circuit TM2 2 is an explanatory diagram showing an example of the operation while measuring the predetermined time Td2. Explanatory drawing which shows the operation example after the timer circuit TM1 has finished counting the first predetermined time Td1, and after the timer circuit TM2 has finished counting the second predetermined time Td2. Diagram showing a configuration example of a constant current circuit Time chart showing an example of each operation of monitoring of power transmission current, mounting detection, and authentication completion in a power transmission device during normal operation in which the power receiving device is placed on the placement surface of the power transmission device Time chart showing an example of each operation of power transmission current monitoring, mounting detection, authentication completion, and foreign object detection in a power transmission device when a metal foreign object is placed alone on the mounting surface of the power transmission device Time chart showing an example of each operation of monitoring of power transmission current, mounting detection, authentication completion, and foreign object detection in the power transmission apparatus when both the metal foreign object and the power receiving apparatus are mounted on the mounting surface of the power transmission apparatus (A), (B) The figure which shows an example of a circuit structure of a mounted detection circuit

  Hereinafter, embodiments of a power receiving device, a power receiving method, and a power transmission system according to the present invention (hereinafter referred to as “this embodiment”) will be described with reference to the drawings. The power transmission system 50 of the present embodiment includes a power transmission device 10 as a primary side and a power reception device 20 as a secondary side (see FIG. 1).

  The power transmission device 10 of the present embodiment detects that an object (for example, the power receiving device 20 or the metal foreign object MTB) is placed (mounted) on a predetermined placement surface (not shown) provided in the power transmission device 10. When the authentication process with the object is successful and it is detected that the placed object is not the metal foreign object MTB, power is transmitted (transmitted) to the power receiving device 20 in a non-contact manner. The power receiving device 20 charges a battery as an example of a rechargeable battery using the power transmitted (transmitted) from the power transmitting device 10.

  In the following description, in non-contact charging, the primary side indicates the side that transmits power, and the secondary side indicates the side that receives power and charges. In addition, a process for supplying electric power is described as “power supply”, a process for storing electric power in a rechargeable battery (battery) is described as “charging”, and both are described separately unless otherwise specified.

  FIG. 1 is a block diagram illustrating an example of a system configuration of a power transmission system 50 according to the present embodiment. The power transmission device 10 is, for example, a charging stand such as a cradle, and specifically includes a control CPU (Central Processing Unit) 11, a power feeding IC (Integrated Circuit) 12, a drive circuit 13, an inverter circuit 14, and an LPF (LPF). Low Pass Filer) 15, mounting detection circuit 16, resonance capacitor 17, foreign object detection circuit 18, and power transmission coil TxC.

  The power receiving device 20 is a data communication device such as a mobile phone, a smartphone, or a tablet terminal. Specifically, the power receiving device 20 is a power receiving coil RxC, a resonance capacitor 21, a rectifying / smoothing circuit 22, and a DC (Direct Current). / DC 23, charger 24, power supply IC 25, constant current circuit 26, and two timer circuits TM1 and TM2.

(Configuration of power transmission device)
The control CPU 11 performs control processing for overall control of operations of each unit constituting the power transmission device 10, signal processing with each unit configuring the power transmission device 10, and determination processing using the signal processing result (for example, Installation detection, authentication completion determination, power supply stop, reset process when power supply is stopped, foreign object detection), or instruction processing to each unit. Further, the control CPU 11 monitors the impedance in the power transmission device 10.

  The power supply IC 12 mainly controls power transmission (power supply) processing from the power transmission device 10 to the power reception device 20 and authentication processing between the power transmission device 10 and the power reception device 20 in accordance with an instruction from the control CPU 11. For example, a voltage necessary for the operation of the drive circuit 13 is supplied to the drive circuit 13. In addition, when the control CPU 11 determines that the metal foreign object MTB is placed on the placement surface of the power transmission device 10, the power feeding IC 12 as an example of the power transmission current control unit is a predetermined period (specifically, The output period of the intermittent transmission current is increased over time t1 to t5) shown in FIG. 7 and switched from, for example, 5 [milliseconds] to 100 [milliseconds] (see FIG. 7).

  In the following description, a power transmission coil TxC is disposed near a predetermined placement surface of the power transmission device 10, and when the power reception device 20 approaches the placement surface, between the power transmission coil TxC and the power reception coil RxC. Then, before power transmission starts, authentication processing is performed between the power transmission device 10 and the power reception device 20.

The power feeding IC 12 includes an envelope detection unit 12a (see FIG. 9A), and an output from the mounting detection circuit 16 described later (that is, a detection voltage V ₃ indicating the output of the envelope detection unit 12a) is mounted. This is supplied to the detection circuit 16. A detailed circuit configuration example of the mounting detection circuit 16 will be described later with reference to FIGS. As will be described later, an operation instruction to the foreign object detection circuit 18 is given from the control CPU 11, but may be given from the power supply IC 12.

  In the present embodiment, the control CPU 11 and the power supply IC 12 are configured separately, but one of them may be included in the other. In other words, the power supply IC 12 may be configured to be included in the control CPU 11, or the control CPU 11 may be configured to be included in the power supply IC 12.

  In addition, after the mounting detection circuit 16 determines that the power receiving device 20 is placed on a predetermined placement surface of the power transmitting device 10, the period during which the constant current circuit 26 of the power receiving device 20 operates (specifically, Based on the constant current flowing at times t1 to t3) shown in FIG. 6, a power transmission current I whose current value is continuously constant flows in the power transmission device 10. For this reason, the power feeding IC 12 transmits a transmission signal in which a predetermined authentication signal is superimposed on the continuous power transmission current I from the power transmission coil TxC. The power supply IC 12 generates, for example, a predetermined signal by performing ASK (Amplitude Shift Keying) or FSK (Frequency Shift Keying) as the authentication signal. The power feeding IC 12 may use a predetermined ID for identifying the power transmission device 10 as an authentication signal, in addition to generating an authentication signal by applying ASK or FSK to the predetermined signal. Thereby, the power feeding IC 12 can easily generate an authentication signal.

  The drive circuit 13 is a clock signal for operating the inverter circuit 14 according to a current (transmission current I) from a DC power supply or a commercial AC power supply (in other words, the inverter circuit 14 converts the DC signal into an AC (Alternative Current)). A signal for determining the frequency of a DC signal (rectangular wave) used for conversion into a signal is generated and output to the inverter circuit 14. The drive circuit 13 may be configured to be included in the inverter circuit 14.

  The inverter circuit 14 converts the DC signal of the transmission current I into an AC signal and outputs it to the LPF 15.

The LPF 15 cuts off a low frequency component (for example, DC component) of the output of the inverter circuit 14 (AC signal of the transmission current I) and outputs it to the resonance capacitor 17. The output of the LPF15 is converted to a voltage, it is supplied to the mounting detection circuit 16 as the input voltage _{V 7.}

In the mounting detection circuit 16 as an example of the mounting detection unit, the power receiving device 20 or the metal foreign object MTB (see FIG. 7) is predetermined during the first predetermined time Td1 corresponding to the mounting detection section shown in FIG. and it determines whether it is placed on the mounting surface of a predetermined condition (i.e., condition of the value of the output voltage V ₆ to be described later) when is satisfied, the power receiving device 20 or the foreign metal substance MTB (see FIG. 7 ) Is detected to be placed on a predetermined placement surface. Here, a detailed circuit configuration example of the mounting detection circuit 16 will be described with reference to FIGS.

  FIGS. 9A and 9B are diagrams illustrating an example of the circuit configuration of the mounting detection circuit 16. The mounting detection circuit 16 includes a first mounting detection circuit unit 16a illustrated in FIG. 9A and a second mounting detection circuit unit 16b illustrated in FIG. 9B. 9A includes an amplifier and two resistors (for example, a resistor having a resistance value R1 = 49.9 [kΩ] and a resistor having a resistance value R2 = 7.5 [kΩ]). Are connected in series.

In FIG. 9 (A), the input voltage _{V 7} as the output of the LPF15 is the division ratio of the resistance values R1, R2 of the two resistors is inputted to the envelope detector 12a of the feed IC12 as voltage V_DETIN. In the envelope detection unit 12a, the detection is an envelope of the voltage V_DETIN, voltage V_DETOUT as detection output is input to the second mounting detection circuit section 16b as detection voltage _{V 3.} The relationship between the detected voltage _{V 3} and the input voltage _{V 7,} for example represented by formula (1).

In FIG. 9 (B), the detected voltage _{V 3,} the resistance (e.g., resistance value R3 = 7.5 [kΩ]) is input to the inverting input terminal of the comparator CMP via a reference voltage _{V 4} the power supply voltage is stepped down There the division ratio between the resistance value R6, R5 of two resistors, the reference divided voltage V ₅ is input to the non-inverting input terminal of the comparator CMP. By a comparator CMP resistance (e.g. resistance R4 = 7.5 [kΩ]), the second mounting detection circuit unit 16b outputs the information about the output voltage _{V 6} to the power supply IC 12.

Here, in FIG. 9 (B), the relationship between the reference divided voltage _{V 5} and the reference voltage _{V 4,} for example when it is indicated by Equation (2), the partial pressure ratio between the resistance value R6, R5 and k1 ( It is shown by the mathematical formula (4). The relationship between the reference divided voltage V ₅ and the output voltage V _6, for example represented by formula (5). In Equation (5), _{k 2} denotes the ratio of the resistance value R4, R3 (see Equation (6)).

Further, in FIG. 9A, when the voltage division ratio between the resistance values R1 and R2 is k ₁ (see Expression (7)), Expression (1) is expressed by Expression (8), so that the output voltage V ₆ and relationship between the input voltage V ₇ is represented by equation (9).

Thus, the mounting detection circuit 16 outputs the information about the output voltage V ₆ calculated by Equation (9) to the feed IC 12. Feeding IC12 is, if more than the output voltage _{V 6,} for example, 1.1 _(V 6> 1.1), the standby state (i.e., state the mounting surface not placed any power transmitting device 10) On the other hand, when the output voltage V ₆ is less than 1.0 (V ₆ ≦ 1.0), for example, the power receiving device 20 is mounted on the mounting detection state (that is, the mounting surface of the power transmitting device 10 is Alternatively, it is determined that a metal foreign object as an example of an object other than the power receiving device 20 is placed.

  In the following description, it is assumed that the mounting detection state may include a state in which the mounting surface is close to the mounting surface even if it is not mounted.

  Note that the mounting detection circuit 16 as an example of the mounting detection unit is a period in which the constant current circuit 26 of the power receiving device 20 described later operates when the power receiving device 20 is mounted on the mounting surface of the power transmitting device 10. (Specifically, since the impedance of the power transmission device 10 changes so as to decrease based on the constant current flowing at time t1 to t3 shown in FIG. 6, for example, according to the impedance monitoring value obtained from the control CPU 11, You may determine with it being a mounting detection state (namely, the state in which the metal foreign material as an example of objects other than the power receiving apparatus 20 or the power receiving apparatus 20 was mounted in the mounting surface of the power transmission apparatus 10).

Further, the mounting detection circuit 16 may determine whether it is in the standby state or the mounting detection state by using the input voltage V ₇ corresponding to the output of the LPF 15. However, since the input voltage V ₇ is a voltage that is not the envelope detection is performed by the envelope detection section 12a, mounted detection circuit 16 uses the input voltage V ₇ corresponding to the output of the LPF 15, the standby state or mounted than to determine whether it is a detection state, by using the output voltage V _6, it can be determined whether it is in the standby state or the mounting detection state with high accuracy.

  The resonance capacitor 17 has, for example, a configuration in which two capacitors are connected in parallel, and causes a resonance action with the power transmission coil TxC. The capacitance value of the resonance capacitor 17 is set such that the resonance frequency is determined by the inductance value of the power transmission coil TxC.

  The foreign object detection circuit 18 monitors a transmission current I indicating a direct current from a direct current power supply or a direct current obtained by rectifying an alternating current from a commercial alternating current power supply (not shown), and an instruction from the control CPU 11 or the power supply IC 12 Accordingly, for example, during the second predetermined time Td2 corresponding to the foreign object detection section shown in FIG. 2B, the timer circuit TM2 of the power receiving device 20 described later measures the second predetermined time Td2 (specifically, Outputs to the control CPU 11 the monitoring result of the transmission current I at times t3 to t4) shown in FIG.

  The control CPU 11 is based on the monitoring result of the power transmission current I in the foreign object detection circuit 18 and the presence / absence of authentication completion between the power transmission device 10 and the power receiving device 20 determined by the control CPU 11 itself (in other words, the success or failure of the authentication process). Then, it is determined whether or not a metal foreign object other than the power receiving device 20 is placed on the placement surface of the power transmission device 10. The control CPU 11 and the foreign object detection circuit 18 constitute a foreign object placement determination unit.

  The foreign object detection circuit 18 is not limited to monitoring the transmission current I, but may monitor other parameters (for example, temperature) and output the temperature monitoring result to the control CPU 11. In this case, the control CPU 11 determines whether or not a metal foreign object other than the power receiving device 20 is placed on the placement surface of the power transmission device 10 based on a comparison result between the temperature monitoring result in the foreign matter detection circuit 18 and a predetermined temperature threshold value. Determine whether.

  The power transmission coil TxC has an intermittent power transmission current I according to the output of the LPF 15 or a power (transmission power) according to the continuous power transmission current I, or an intermittent power transmission current I according to the output of the LPF 15 or a continuous power. A transmission signal in which a predetermined authentication signal is superimposed on power (transmission power) corresponding to the transmission current I is transmitted in a contactless manner.

(Configuration of power receiving device)
The power receiving coil RxC receives the power signal or the transmission signal transmitted from the power transmitting coil TxC in a non-contact manner when the power receiving device 20 approaches or is placed on the mounting surface of the power transmitting device 10. To do. A voltage (induced voltage) induced in the power receiving coil RxC by non-contact power transmission from the power transmitting coil TxC is input to the rectifying and smoothing circuit 22 via the resonance capacitor 21.

  The resonance capacitor 21 has, for example, a configuration in which two capacitors are connected in parallel, and causes a resonance action with the power receiving coil RxC. The capacitance value of the resonance capacitor 21 is set such that the resonance frequency is determined by the inductance value of the power receiving coil RxC.

The rectifying / smoothing circuit 22 includes a rectifying circuit and a smoothing circuit, and performs a rectifying process and a smoothing process on a power signal or a transmission signal received by the power receiving coil RxC. As shown in FIG. 2B, when the power receiving device 20 approaches the placement surface of the power transmission device 10, the power transmission current I in the power transmission device 10 increases. ₂ ) increases.

  The DC / DC 23 has a switching element (not shown) and switches on or off according to an operation control signal from the power supply IC 25. For example, when the DC / DC 23 is in an on state, the DC / DC 23 is a predetermined unit required to charge a battery as an example of a rechargeable battery with the power transmitted from the power transmission device 10 based on the output of the rectifying and smoothing circuit 22. The voltage is transformed (stepped down) to a DC voltage or a predetermined DC voltage necessary for the operation of the system (computer system) of the power receiving device 20. On the other hand, when the DC / DC 23 is in the OFF state, the output of the rectifying and smoothing circuit 22 is not input.

  The charger 24 charges the battery or operates the system of the power receiving device 20 according to the DC voltage transformed (stepped down) by the DC / DC 23.

  The power feeding IC 25 separates the power signal included in the transmission signal transmitted from the power transmission device 10 and the authentication signal after the timer circuit TM1 starts measuring the first predetermined time Td1. The power supply IC 25 as an example of an authentication unit performs an authentication process between the power transmission device 10 and the power reception device 20 using an authentication signal.

  In addition, the power feeding IC 25 receives the second predetermined time Td2 from the timer circuit TM2 after the timer circuit TM1 has timed the first predetermined time Td1 (in other words, after the time measurement of the first predetermined time Td1 has ended). In addition, after the timer circuit TM2 starts measuring the second predetermined time Td2, the DC / DC 23 is switched to the OFF state, whereby the power receiving coil RxC and the DC / DC 23 are in a non-conductive state ( Switch to the off state.

  On the other hand, the power supply IC 25 switches the DC / DC 23 to the ON state after the timer circuit TM2 has timed the second predetermined time Td2 (in other words, after the time measurement of the second predetermined time Td2 has been completed) (FIG. 2 ( B)), using the power transmitted from the power transmission device 10, the battery is charged to the charger 24 via the DC / DC 23 that is in a conductive state (on state) with the power receiving coil RxC. Make it.

  The constant current circuit 26 receives an operation control signal from the timer circuit TM1 while the timer circuit TM1 measures the first predetermined time Td1, so that a predetermined constant current flows (see FIG. 5). Here, a circuit configuration example of the constant current circuit 26 will be described with reference to FIG.

  FIG. 5 is a diagram illustrating a configuration example of the constant current circuit 26. The constant current circuit 26 shown in FIG. 5 includes, for example, a circuit in which a first transistor element FT1, a constant current element CT1, a second transistor element FT2, and a resistor having a resistance value of 270 [Ω] are connected in series; In this configuration, the element FT3 and a circuit in which a resistor having a resistance value of 10 [Ω] is connected in series are connected in parallel. The second transistor element FT2 and the third transistor element FT3 constitute a current mirror circuit to which the respective gate terminals are connected.

  The timer circuit TM1 operates the constant current circuit 26 for a certain period (for example, the first predetermined time Td1) for the authentication process between the power transmitting apparatus 10 and the power receiving apparatus 20. When the constant current circuit 26 operates, a constant current flows through the power receiving device 20, so that the constant current flows so that the impedance of the power transmitting device 10 that the power receiving device 20 approaches or is placed on the placement surface is reduced. The power transmission current I in the power transmission device 10 is increased. As a result, the difference between the authentication signal and the power waveform (for example, a rectangular wave) becomes clear, and the power feeding IC 25 of the power receiving device 20 can separate the power signal and the authentication signal with high accuracy, and the authentication process can be performed. It can be done easily.

5, when the rectified and smoothed output voltage V ₂ exceeds a certain value, the timer circuit TM1 can start the operation. Therefore, the timer circuit TM1 starts measuring the first predetermined time Td1, and inputs an operation control signal for turning on the constant current circuit 26 to the gate terminal of the first transistor element FT1.

  The first transistor element FT1 is a switching for switching on or off the operation of the constant current circuit 26 depending on whether the operation control signal from the timer circuit TM1 is Hi (high) or Lo (low). It is an element.

  A period from when the timer circuit TM1 starts measuring the first predetermined time Td1 until the time measurement of the first predetermined time Td1 ends, or until the authentication process between the power transmitting apparatus 10 and the power receiving apparatus 20 is successful. In the period, since the operation control signal from the timer circuit TM1 is in the Hi state, the constant current circuit 26 operates and a constant current of 270 [milliA] flows. On the other hand, after the timing of the first predetermined time Td1 is completed or after the authentication process between the power transmission device 10 and the power reception device 20 is successful, the operation control signal from the timer circuit TM1 is in the Lo state. The current circuit 26 stops its operation and no constant current flows.

  FIG. 2A is a diagram illustrating an example of a connection relationship between the two timer circuits TM <b> 1 and TM <b> 2, the constant current circuit 26, and the DC / DC 23 of the power receiving device 20. FIG. 2B is an explanatory diagram of a mounting detection section and a foreign object detection section in the power transmission device 10. The horizontal axis in FIG. 2B represents time, and the vertical axis in FIG. 2B represents the magnitude of the transmission current I in the power transmission device 10. A dotted line shown in FIG. 2B indicates the mounting detection threshold value Ith1. The mounting detection threshold value Ith1 is a threshold value provided for determining whether any object (for example, the power receiving device 20 or the metal foreign object MTB) is placed on the placement surface of the power transmission device 10.

Before the timer circuit TM1 measures the first predetermined time Td1 (in other words, before the power reception coil RxC approaches the power transmission coil TxC), the power transmission current in the power transmission device 10 is an intermittent current, and the magnitude of this power transmission current is large. is is is allowed (in other words, the rectified smoothed output voltage V ₂ exceeds a certain value) operating the timer circuit TM1 when the power to the power receiving device 20 from the power transmission device 10 is transmission of the order of magnitude.

The timer circuit TM1, when rectified smoothed output voltage V ₂ exceeds a certain value, for counting a first predetermined time period Td1 starts counting the first predetermined time Td1. As described above, the timer circuit TM1 outputs an operation control signal for turning on the operation of the constant current circuit 26 to the constant current circuit 26 while measuring the first predetermined time Td1. In the present embodiment, the first predetermined time Td1 is, for example, 1 [second], and serves as a mounting detection section in which it is determined whether or not the power receiving device 20 or the metal foreign object is mounted on the mounting surface of the power transmission device 10. Have

  The start timing of the first predetermined time Td1 is set when the power receiving coil RxC of the power receiving device 20 approaches the power transmitting coil TxC of the power transmitting device 10 (see time t0 shown in FIG. 2A) or when the power transmitting device 10 is mounted. This is the time when the power receiving device 20 is placed on the mounting surface (see time t1 shown in FIG. 6).

  The timer circuit TM2 performs authentication processing when the timer circuit TM1 finishes counting the first predetermined time Td1 (see time t3 shown in FIG. 2A or FIG. 6) or between the power transmission device 10 and the power reception device 20. Is successful (see time t2 shown in FIG. 6), the measurement of the second predetermined time Td2 is started to measure the second predetermined time Td2. In the present embodiment, the second predetermined time Td2 is, for example, 0.5 [second], and is a foreign object detection section in which it is determined whether or not the object mounted on the placement surface of the power transmission device 10 is a foreign object. Have a role.

  Next, the operation during or before and after the first predetermined time Td1 and the second predetermined time Td2 of the two timer circuits TM1 and TM2, the constant current circuit 26 and the DC / DC 23 of the power receiving device 20 are shown in FIG. A), FIG. 3B and FIG. 4 will be described.

  FIG. 3A is an explanatory diagram illustrating an operation example during which the timer circuit TM1 measures the first predetermined time Td1. FIG. 3B is an explanatory diagram illustrating an operation example after the timer circuit TM1 finishes measuring the first predetermined time Td1 and while the timer circuit TM2 measures the second predetermined time Td2. FIG. 4 is an explanatory diagram showing an operation example after the timer circuit TM1 finishes counting the first predetermined time Td1 and after the timer circuit TM2 finishes counting the second predetermined time Td2.

In FIG. 3 (A), the rectifying and smoothing the output voltage V ₂ exceeds a certain value, the timer circuit TM1 starts operating. While the timer circuit TM1 measures the first predetermined time Td1, an operation control signal for turning on the operation of the constant current circuit 26 is input from the timer circuit TM1 to the constant current circuit 26. A current flows (see FIG. 5).

  In FIG. 3B, the operation of the constant current circuit 26 is in an OFF state after the timer circuit TM1 finishes measuring the first predetermined time Td1 and while the timer circuit TM2 measures the second predetermined time Td2. Therefore, when viewed from the rectified and smoothed output side, the (input) impedance on the constant current circuit 26 side becomes high, and the current of the rectified and smoothed output (rectified and smoothed output current) is input to the DC / DC 23. However, the power feeding IC 25 switches the DC / DC 23 to the OFF state while the timer circuit TM2 measures the second predetermined time Td2. For this reason, the battery is not charged in the power receiving device 20.

  In FIG. 4, after the timer circuit TM2 finishes counting the second predetermined time Td2, the power feeding IC 25 switches the DC / DC 23 to the on state. For this reason, the rectified and smoothed output current flows to the charger 24 via the DC / DC 23, so that the battery is charged in the power receiving device 20.

(Operation of the power transmission system when the power receiving device is mounted on the mounting surface of the power transmitting device)
Next, a time-series operation procedure of the power transmission device 10 during normal operation in which the power reception device 20 is placed on the placement surface of the power transmission device 10 will be described with reference to FIG. FIG. 6 is a time chart illustrating an example of each operation of power transmission current monitoring, mounting detection, and authentication completion in a power transmission device during normal operation in which the power reception device is placed on the placement surface of the power transmission device.

  In FIG. 6, until the time t1 (in other words, the time when it is detected that the power receiving device 20 is placed on the placement surface of the power transmitting device 10), the power transmitting device 10 does not satisfy the mounting detection threshold Ith1. An intermittent power transmission current I flows (intermittent power transmission). The current value of the intermittent power transmission current I at the time of intermittent power transmission is a current value necessary for starting the timer circuit TM1 of the power receiving device 20 and executing the authentication process between the power transmitting device 10 and the power receiving device 20. The first role and the second role of having a current value for starting detection of whether or not the power receiving device 20 is placed on the placement surface of the power transmission device 10 are provided.

  In addition, since the power transmission device 10 cannot predict when the power reception device 20 is placed on the placement surface of the power transmission device 10 by the user, the power reception device 20 is placed on the placement surface. Compared to the case where the continuous power transmission current I is supplied, the increase in the power consumption in the power transmission device 10 can be suppressed by flowing the intermittent power transmission current I before the detection that the power transmission device 10 is placed.

Feeding IC12, when it is determined that the mounting detecting circuit 16 outputs the power reception device by the voltage V ₆ based on 20 or metal foreign substance of MTB is placed on the mounting surface of the power transmitting device 10 (see time t1), power supply A predetermined mounting detection interrupt signal is output from the IC 12. To synchronize with the output of the mounting detection interrupt signal, the rectified and smoothed output voltage V ₂ in the power receiving apparatus 20 exceeds a certain value, the timer circuit TM1 starts counting the first predetermined time Td1 (e.g. 1 [sec]) .

  While the timer circuit TM1 counts the first predetermined time Td1, authentication processing is performed between the power transmitting device 10 and the power receiving device 20, and a constant current flows as the constant current circuit 26 operates in the power receiving device 20. Therefore, it changes so that the impedance of the power transmission apparatus 10 may become small, and the current value of the transmission current I in the power transmission apparatus 10 becomes larger than the current value at the time of intermittent power transmission.

  When the authentication process between the power transmitting apparatus 10 and the power receiving apparatus 20 is successful (see time t2), a predetermined authentication completion interrupt signal is output from the power feeding IC 12. In order to synchronize with the output of the authentication completion interrupt signal, in the power receiving device 20, the second timer circuit TM2 starts measuring a second predetermined time Td2 (for example, 0.5 [seconds]) according to an instruction from the power supply IC 25. When the timer circuit TM1 finishes counting the first predetermined time Td1 (see time t3), the power feeding IC 25 starts measuring the second predetermined time Td2 (for example, 0.5 [second]) of the timer circuit TM2. You may let them.

  In FIG. 6, an example in which the power receiving device 20 is placed on the placement surface of the power transmission device 10 is shown. Therefore, the authentication process between the power transmission device 10 and the power receiving device 20 is successful, and the second timer circuit Since the constant current circuit 26 does not operate while TM2 measures the second predetermined time Td2, the power transmission current I in the power transmission device 10 falls below the mounting detection threshold value Ith1. In the present embodiment, while the timer circuit TM2 measures the second predetermined time Td2 (foreign matter detection section), the mounting detection threshold value Ith1 indicates whether or not the foreign matter has been placed on the placement surface of the power transmission device 10. It has a role as a foreign object detection threshold for determination.

  While the timer circuit TM2 measures the second predetermined time Td2 (see times t3 to t4), the operation of the constant current circuit 26 is in the off state, and the power transmission device is compared with the case where the operation of the constant current circuit 26 is in the on state. Since the impedance of 10 changes so as to increase, the power transmission current I in the power transmission device 10 is less than the mounting detection threshold Ith1.

  For this reason, since the power transmission device 10 can determine that the power receiving device 20 is placed on the placement surface instead of the metal foreign object MTB, the timer circuit TM2 finishes counting the second predetermined time Td2. In the power transmission device 10, a continuous power transmission current I having a constant current value flows (continuous power transmission after time t4).

  In FIG. 6, the authentication process between the power transmission device 10 and the power reception device 20 is not limited to the time t1 to t2, and may be performed when a continuous power transmission current I after the time t4 flows. .

(Operation of the power transmission system when a metallic foreign object is placed alone on the placement surface of the power transmission device)
Next, a time-series operation procedure of the power transmission device 10 when the metal foreign object MTB is mounted on the mounting surface of the power transmission device 10 alone will be described with reference to FIG. FIG. 7 is a time showing an example of each operation of power transmission current monitoring, mounting detection, authentication completion, and foreign material detection in the power transmission device 10 when the metal foreign material MTB is placed on the placement surface of the power transmission device 10 alone. It is a chart. In the description of FIG. 7, description of contents overlapping with the description of FIG. 6 is simplified or omitted, and different contents are described.

In FIG. 7, the power supply IC 12 determines that the power receiving device 20 or the metal foreign object MTB is placed on the placement surface of the power transmission device 10 based on the output voltage V ₆ of the mounting detection circuit 16 at time t1. Therefore, similarly to FIG. 6, the magnitude of the power transmission current I in the power transmission device 10 is larger than the magnitude of the power transmission current I during intermittent power transmission. However, since FIG. 7 shows an operation example when the metal foreign object MTB is placed on the placement surface of the power transmission device 10, the authentication signal is not transmitted from the power transmission device 10 to the power reception device 20, and the power transmission device 10 and the power receiving apparatus 20 fail. That is, the authentication completion interrupt signal is not output from the power feeding IC 12 at time t1 in FIG.

  Therefore, the power feeding IC 12 of the power transmission device 10 performs authentication processing when the power receiving device 20 is placed on the placement surface during a predetermined period (for example, 5 [seconds] from time t1 to t5) from time t1. In order to facilitate the success, the output cycle (for example, 100) of the transmission current I is increased so as to increase the output cycle (for example, 5 [milliseconds]) of the transmission current I during intermittent power transmission (intermittent power transmission (5 ms)) until time t1. [Milliseconds]) (intermittent power transmission (100 ms)).

  However, in FIG. 7, the control CPU 11 or the power supply IC 12 of the power transmission device 10 has a period (time) of intermittent power transmission (100 ms) even if the authentication process between the power transmission device 10 and the power reception device 20 fails at the time t1. Until t1 to t5) is finished, it is not determined that the metal foreign matter MTB has been detected.

  If the authentication process between the power transmitting device 10 and the power receiving device 20 is not successful even after a predetermined period of time has elapsed from time t1, the control CPU 11 of the power transmitting device 10 starts from the foreign object detection circuit 18. Based on the output of, it is detected that the object placed on the placement surface at time t1 is not the power receiving device 20 but the metal foreign object MTB. In this case, a predetermined foreign object detection interrupt signal is output from the power feeding IC 12.

  After the time t5, the control CPU 11 or the power feeding IC 12 of the power transmission device 10 stops the output of the intermittent transmission current I with an output cycle of 100 [milliseconds], and has an output cycle of 5 [milliseconds] before the time t1. It switches so that it may return to the output of intermittent transmission current I. However, since the metallic foreign object MTB is placed on the placement surface of the power transmission device 10, the impedance of the power transmission device 10 decreases, and the power transmission current I after time t5 is the power transmission current I before time t1. Larger than

  Note that the operation of the power transmission device 10 illustrated in FIG. 7 is not limited to the operation when the metal foreign object MTB is placed on or close to the placement surface of the power transmission device 10, and the power receiving device 20 and a very large metal You may apply to the operation | movement when the foreign material MTB is mounted on a mounting surface together, or when approaching. If a large foreign metal MTB is placed or approaches the power receiving coil 20 of the power receiving device 20 together with the power receiving device 20, there is a high possibility that the authentication process will fail without being transmitted to the power receiving device 20. is there.

(Operation of the power transmission system when the metal foreign object and the power receiving device are mounted on the mounting surface of the power transmitting device)
Next, a time-series operation procedure of the power transmission device 10 when both the metal foreign object MTB and the power receiving device 20 are placed on the placement surface of the power transmission device 10 will be described with reference to FIG. FIG. 8 shows each of the operations of power transmission current monitoring, mounting detection, authentication completion, and foreign object detection in the power transmission apparatus 10 when both the metal foreign object MTB and the power receiving apparatus 20 are mounted on the mounting surface of the power transmission apparatus 10. It is a time chart which shows an example. In the description of FIG. 8, description of contents overlapping with the description of FIG. 6 is simplified or omitted, and different contents will be described.

  In FIG. 8, unlike FIG. 7, an authentication signal is transmitted to the power receiving device 20 because a small metal foreign matter MTB is placed with or close to the power receiving coil RxC of the power receiving device 20. In this example, the authentication process is successful.

  Further, in the foreign object detection section (see times t3 to t4) in FIG. 8, the operation of the constant current circuit 26 of the power receiving device 20 is in an off state, but since there is a metal foreign object MTB near the power transmitting device 10, The impedance changes so as to be smaller than the impedance in the foreign object detection section (see times t3 to t4) shown in FIG. For this reason, the power transmission current I in the foreign object detection section (see times t3 to t4) in FIG. 8 is larger than the mounting detection threshold value Ith1 that serves as a foreign object detection threshold value.

  However, in FIG. 8, since the authentication process between the power transmission device 10 and the power receiving device 20 is successful, when the metal foreign matter MTB is placed on or approaches the power transmission device 10 together with the power receiving device 20, continuous power transmission from the power transmission device 10. As a result, a large amount of electric power is transmitted and the metal foreign matter MTB generates heat, which is not preferable in consideration of actual operation.

  Therefore, in FIG. 8, unlike FIG. 6, the power supply IC 12 outputs a predetermined authentication interrupt signal for a predetermined period (for example, 2.. When 5 [seconds] (= 0.5 [second] from time t2 to t6 + 2.0 [second] from time t6 to t7)) has elapsed, power transmission according to continuous transmission current I ( (Continuous power transmission) is stopped (see time t7). 0.5 [seconds] from time t2 to time t6 corresponds to, for example, the second predetermined time Td2 measured by the timer circuit TM2. 2.0 [seconds] from time t6 to time t7 is a predetermined grace period for the power transmission apparatus 10 to temporarily continuously transmit power.

  That is, the power feeding IC 12 makes a primary determination as to whether or not the metal foreign matter MTB is placed in the first half of 0.5 [second] out of the above 2.5 [second], and the second half of 2.0 [second]. Second], a secondary determination is made as to whether or not the metal foreign object MTB has been placed. After time t7, the control CPU 11 of the power transmission device 10 determines that the objects placed on the placement surface at the time t1 are the power receiving device 20 and the metal foreign matter MTB based on the output from the foreign matter detection circuit 18. Detect. In this case, a predetermined foreign object detection interrupt signal is output from the power feeding IC 12.

  After time t7, the control CPU 11 or the power feeding IC 12 of the power transmission device 10 stops the output of the continuous power transmission current I from time t4 to t7, and returns it to the output of the intermittent power transmission current I as before time t1. Switch to. However, since the metal foreign object MTB is placed on the placement surface of the power transmission device 10, the impedance of the power transmission device 10 decreases, and the power transmission current I after time t7 is the power transmission current I before time t1. Larger than

As described above, in the power transmission system 50 according to the present embodiment, the power transmission device 10 transmits the power corresponding to the minimum intermittent power transmission necessary for the operation of the timer circuit TM1 of the power reception device 20 in a contactless manner. It is detected that 20 is placed on a predetermined placement surface. The power receiving device 20 receives power corresponding to the intermittent power transmission current from the power transmitting device 10 in a non-contact manner, and an induced voltage (rectified smoothed output voltage V ₂ ) corresponding to the received power exceeds a certain value. While the timer circuit TM1 measures the first predetermined time Td1, a predetermined constant current flows in the constant current circuit 26 in accordance with the operation control signal from the timer circuit TM1. Further, the power transmission device 10 detects that the power reception device 20 is placed on a predetermined placement surface according to a change in impedance of the power transmission device 10 due to a predetermined constant current flowing in the power reception device 20. .

  As a result, in the power transmission system 50, the power transmission device 10 transmits the power corresponding to the minimum intermittent transmission current necessary for the operation of the timer circuit TM1 of the power reception device 20 in a non-contact manner, thereby suppressing an increase in power consumption. can do. Further, when the power receiving device 20 approaches the power transmitting device 10, a constant current flows while the timer circuit TM1 counts the first predetermined time Td1 based on the power corresponding to the intermittent power transmitting current. By causing a constant current to flow through the device 20, a change in impedance in the power transmission device 10 becomes large, thereby causing the power transmission device 10 to recognize that the power reception device 20 is placed on the placement surface of the power transmission device 10. it can.

  In the power transmission system 50, the power transmission device 10 detects that the power receiving device 20 is placed on a predetermined placement surface, and then continuously transmits power based on a predetermined constant current generated in the power receiving device 20. A transmission signal in which a predetermined authentication signal is superimposed on a power signal corresponding to the current is transmitted from the power transmission coil TxC. In addition, since the power receiving device 20 performs an authentication process with the power transmission device 10 based on the transmission signal transmitted from the power transmission device 10 after the timer circuit TM1 starts measuring the first predetermined time Td1, The separation accuracy of the authentication signal in the device 20 can be improved, and highly accurate authentication processing can be performed with the power transmission device 10.

  In the power transmission system 50, the power receiving device 20 further counts the second predetermined time Td2 after the first predetermined time Td1 is timed or after the authentication with the power transmission device 10 is successful. After the completion, if the power transmission device 10 determines that the object placed on the power transmission device 10 is the power reception device 20 during the second predetermined time Td2, the power corresponding to the continuous transmission current is transmitted from the power transmission coil TxC. Therefore, the battery can be safely charged via the DC / DC 23 by conducting between the power receiving coil RxC and the DC / DC 23.

  Further, in the power transmission system 50, the power transmission device 10 has a power receiving device 20 on a predetermined placement surface based on both the magnitude of the power transmission current to the power transmission coil TxC and the success or failure of authentication with the power receiving device 20. It is possible to detect that a metal foreign matter MTB other than that is placed, and after determining that the metal foreign matter MTB has been placed on a predetermined placement surface, an intermittent transmission current Since the output cycle is increased, it is possible to improve the detection accuracy of the authentication signal included in the transmission signal in the authentication with the power receiving device 20, and the authentication can be performed efficiently.

  Moreover, since the power transmission system 50 reduces the output cycle of intermittent power transmission current when authentication with the power receiving device 20 fails during a predetermined period, the power transmitting device 10 or the metal foreign object It is possible to suppress an increase in power consumption of a transmission current output until it is detected that the MTB is placed on the placement surface.

  Further, in the power transmission system 50, the power transmission device 10 has the power receiving device 20 mounted on the mounting surface when the power transmission current after the output cycle increases becomes less than a predetermined foreign object detection threshold. Since the possibility is high, an increase in power consumption can be suppressed by reducing the output cycle of intermittent transmission current.

  In the power transmission system 50, the power transmission device 10 determines that the magnitude of the transmission current to the power transmission coil TxC is equal to the predetermined mounting detection threshold Ith1 (foreign object detection threshold) while the timer circuit TM2 measures the second predetermined time Td2. When exceeding, since it is thought that the impedance in the power transmission device 10 has decreased, it is possible to detect that the metal foreign matter MTB other than the power receiving device 20 is placed on the placement surface.

  Further, in the power transmission system 50, the power transmission device 10 is configured such that the transmission current to the power transmission coil TxC from the time when the timer circuit TM2 measures the second predetermined time Td2 until a predetermined grace period (for example, 2 seconds) elapses. When the mounting detection threshold value Ith1 (foreign matter detection threshold value) is exceeded, it is considered that the state where the impedance of the power transmission device 10 is reduced continues, so that the metal foreign matter MTB other than the power receiving device 20 is placed on the placement surface. It can be detected with high accuracy. Further, when the power transmission device 10 determines that the metal foreign object MTB has been placed on the predetermined placement surface, the power transmission device 10 starts from the continuous power transmission current after the timer circuit TM2 measures the second predetermined time Td2. Since it switches to intermittent power transmission current, the increase in power consumption can be suppressed.

  Finally, the configuration, operation, and effect of the power reception device, power reception method, and power transmission system according to the present invention will be described.

  In one embodiment of the present invention, a power receiving coil that receives power corresponding to an intermittent power transmission current from a power transmitting device in a contactless manner, and an induced voltage corresponding to the power received by the power receiving coil exceeds a predetermined value. A first timer circuit that counts a first predetermined time; and while the first timer circuit counts the first predetermined time, a predetermined constant current is generated according to an operation control signal from the first timer circuit. And a constant current circuit that flows.

  According to this configuration, the power receiving device receives the power corresponding to the intermittent power transmission current from the power transmission device in a contactless manner, and when the induced voltage corresponding to the received power exceeds a predetermined value, the first timer While the circuit measures the first predetermined time, a predetermined constant current flows in the constant current circuit in accordance with the operation control signal from the first timer circuit.

  Accordingly, when the power receiving device approaches the power transmitting device, the first timer circuit is set to the first predetermined value based on the power corresponding to the minimum intermittent power transmission current necessary for the operation of the first timer circuit of the power receiving device. Since a constant current flows while timing the time, the constant current flows through the power receiving device, which increases the impedance change in the power transmitting device, and informs the power transmitting device that the power receiving device is mounted on the mounting surface of the power transmitting device. Can be recognized.

  In one embodiment of the present invention, after the first timer circuit starts counting the first predetermined time, a predetermined authentication is performed on a power signal corresponding to a continuous transmission current based on the predetermined constant current. The power receiving device further includes an authentication unit that authenticates with the power transmission device based on a transmission signal on which the signal is superimposed.

  According to this configuration, after the first timer circuit starts measuring the first predetermined time, the power receiving device generates a predetermined power signal corresponding to the continuous power transmission current from the power transmission device based on the predetermined constant current. Authentication is performed with the power transmission device based on the transmission signal on which the authentication signal is superimposed, so that the accuracy of separation of the authentication signal in the power receiving device can be improved, and highly accurate authentication processing is performed with the power transmission device. It can be carried out.

  In addition, according to an embodiment of the present invention, the DC transformer unit that transforms the induced voltage into a predetermined DC voltage and the second predetermined time, or after the authentication between the power transmission device succeeds, the second A power receiving device, further comprising a second timer circuit for measuring a predetermined time, wherein the power receiving coil and the DC transformer unit are non-conductive while the second timer circuit measures the second predetermined time. It is.

  According to this configuration, the power receiving apparatus loads the power on the power transmission apparatus after the first predetermined time is measured or after the second timer circuit measures the second predetermined time after the authentication with the power transmission apparatus is successful. As a foreign object detection section that makes the power transmission apparatus determine whether the figurine is a metal foreign object or a power receiving device, in this foreign object detection section, the start of charging in the power receiving device is deferred by making the receiving coil and the DC transformer non-conductive. be able to.

  In addition, according to an embodiment of the present invention, the DC transformer unit that transforms the induced voltage into a predetermined DC voltage and the second predetermined time, or after the authentication between the power transmission device succeeds, the second A second timer circuit that counts a predetermined time; and a charge control unit that charges a rechargeable battery based on the power received by the power receiving coil, wherein the second timer circuit includes the second timer circuit. After counting the second predetermined time, based on the power continuously transmitted from the power transmission coil, the rechargeable battery is charged via the DC transformer unit that is electrically connected to the power receiving coil. It is a power receiving device.

  According to this configuration, the power receiving device can count the first predetermined time or after the authentication with the power transmitting device has succeeded, and further after the second timer circuit finishes counting the second predetermined time, 2 When it is determined that the object placed on the power transmission device is a power reception device during a predetermined time, power corresponding to a continuous transmission current is transmitted from the power transmission coil. Can be safely charged via the DC transformer.

  One embodiment of the present invention is a power receiving method in a power receiving device, the step of receiving power in a power receiving coil in a contactless manner from the power transmitting device in accordance with an intermittent power transmission current, and power received by the power receiving coil. When the induced voltage corresponding to the electric power exceeds a predetermined value, the first timer circuit counts the first predetermined time, and the first timer circuit counts the first predetermined time while the first timer circuit counts the first predetermined time. And a step in which a predetermined constant current flows in the constant current circuit in response to an operation control signal from the circuit.

  According to this method, the power receiving device receives the power corresponding to the intermittent power transmission current from the power transmission device in a non-contact manner, and when the induced voltage corresponding to the received power exceeds a predetermined value, the first timer While the circuit measures the first predetermined time, a predetermined constant current flows in the constant current circuit in accordance with the operation control signal from the first timer circuit.

  Accordingly, when the power receiving device approaches the power transmitting device, the first timer circuit is set to the first predetermined value based on the power corresponding to the minimum intermittent power transmission current necessary for the operation of the first timer circuit of the power receiving device. Since a constant current flows while timing the time, the constant current flows through the power receiving device, which increases the impedance change in the power transmitting device, and informs the power transmitting device that the power receiving device is mounted on the mounting surface of the power transmitting device. Can be recognized.

  Moreover, one embodiment of the present invention is a power transmission system including a power transmission device and a power reception device, wherein the power transmission device transmits power corresponding to an intermittent power transmission current in a contactless manner, A placement detector that detects that the power receiving device has been placed on a predetermined placement surface, the power receiving device receiving power received from the power transmission coil, and the power receiving coil. A first timer circuit that counts a first predetermined time when an induced voltage corresponding to the power received by the power exceeds a predetermined value; and while the first timer circuit counts the first predetermined time, A constant current circuit through which a predetermined constant current flows in response to an operation control signal from one timer circuit, wherein the position detection unit according to a change in impedance in the power transmission device based on the predetermined constant current The power receiving device It detects that it has been placed on the predetermined mounting surface, a power transmission system.

  In this configuration, the power transmission device transmits the power corresponding to the minimum intermittent power transmission current necessary for the operation of the first timer circuit of the power reception device in a non-contact manner, and the power reception device is placed on a predetermined placement surface. It is detected that The power receiving device receives the power corresponding to the intermittent power transmission current from the power transmission device in a non-contact manner, and when the induced voltage corresponding to the received power exceeds a predetermined value, the first timer circuit performs the first predetermined time. During the time measurement, a predetermined constant current flows in the constant current circuit according to the operation control signal from the first timer circuit. In addition, the power transmission device detects that the power reception device is placed on a predetermined placement surface according to a change in impedance of the power transmission device due to a predetermined constant current flowing in the power reception device.

  Thereby, in the power transmission system, the power transmission device transmits power according to the minimum intermittent power transmission current necessary for the operation of the first timer circuit of the power reception device in a non-contact manner, thereby suppressing an increase in power consumption. Can do. Further, when the power receiving device approaches the power transmitting device, a constant current flows while the first timer circuit counts the first predetermined time based on the power corresponding to the intermittent power transmitting current. When the constant current flows, the change in impedance in the power transmission device increases, so that the power transmission device can recognize that the power reception device is placed on the placement surface of the power transmission device.

  In one embodiment of the present invention, the power transmission device is configured to change the power reception device to the predetermined constant current after the placement detection unit detects that the power reception device is placed on the predetermined placement surface. A transmission signal in which a predetermined authentication signal is superimposed on a power signal corresponding to a continuous transmission current based on the power is transmitted from the power transmission coil, and the power receiving device starts counting the first predetermined time by the first timer circuit Then, the power transmission system further includes an authentication unit that authenticates with the power transmission device based on the transmission signal transmitted from the power transmission coil.

  According to this configuration, in the power transmission system, the power transmission device detects that the power reception device is placed on a predetermined placement surface, and then continuously transmits power based on the predetermined constant current generated in the power reception device. A transmission signal in which a predetermined authentication signal is superimposed on a power signal corresponding to the current is transmitted from the power transmission coil. In addition, since the power receiving device performs authentication with the power transmission device based on the transmission signal transmitted from the power transmission device after the first timer circuit starts measuring the first predetermined time, the authentication signal in the power reception device Separation accuracy can be improved, and highly accurate authentication processing can be performed with the power transmission apparatus.

  Further, according to an embodiment of the present invention, the power receiving device has succeeded in authentication between the direct current transformer that transforms the induced voltage into a predetermined direct current voltage and the time measurement of the first predetermined time or the power transmission device. And a charging control unit for charging the rechargeable battery based on the power received by the power receiving coil, and the power transmission device includes the second timer circuit that counts the second predetermined time. After a predetermined time has elapsed, power based on a continuous transmission current is transmitted from the power transmission coil in a non-contact manner, and the charging control unit is configured to transmit the power transmission after the second timer circuit has timed the second predetermined time. In the power transmission system, the rechargeable battery is charged through the direct current transformer that is electrically connected to the power receiving coil based on the power transmitted from the coil.

  According to this configuration, in the power transmission system, the power receiving device counts the second predetermined time after the first predetermined time is measured or after the authentication with the power transmission device is successful. When the power transmission device determines that the object placed on the power transmission device is the power reception device during the second predetermined time, power corresponding to the continuous transmission current is transmitted from the power transmission coil. By conducting between the coil and the direct current transformer, charging of the rechargeable battery via the direct current transformer can be performed safely.

  In one embodiment of the present invention, the power transmission device receives the power reception on the predetermined placement surface based on a magnitude of a power transmission current to the power transmission coil and success or failure of authentication with the power reception device. After the foreign object placement determination unit detects that a metal foreign object other than the apparatus has been placed and the foreign object placement judgment unit determines that the metal foreign object has been placed on the predetermined placement surface. A power transmission system further comprising: a power transmission current control unit that increases an output cycle of the intermittent power transmission current over a predetermined period.

  According to this configuration, in the power transmission system, the power transmission device is a device other than the power reception device on a predetermined placement surface based on both the magnitude of the power transmission current to the power transmission coil and the success or failure of authentication with the power reception device. It is possible to detect that the metal foreign object has been placed, and after determining that the metal foreign object has been placed on the predetermined placement surface, the output cycle of the intermittent transmission current is determined over a predetermined period. Therefore, the detection accuracy of the authentication signal included in the transmission signal can be improved in the authentication with the power receiving apparatus, and the authentication can be performed efficiently.

  In one embodiment of the present invention, the power transmission current control unit decreases the output cycle of the intermittent power transmission current when authentication between the power transmission device and the power receiving device fails in the predetermined period. It is a power transmission system.

  According to this configuration, the power transmission system reduces the output cycle of the intermittent power transmission current when authentication between the power transmission device and the power receiving device fails in a predetermined period. The increase in power consumption of the transmission current that is output until it is detected that is placed on the placement surface can be suppressed.

  Further, according to an embodiment of the present invention, the transmission current control unit outputs the intermittent transmission current when the transmission current after the output cycle increases becomes less than a predetermined foreign object detection threshold. A power transmission system that reduces the period.

  According to this configuration, in the power transmission system, when the power transmission current after the output cycle increases is less than the predetermined foreign object detection threshold, the power transmission device is placed on the placement surface. Therefore, the increase in power consumption can be suppressed by reducing the output cycle of intermittent transmission current.

  Further, according to an embodiment of the present invention, the power receiving device includes a second timer circuit that counts a second predetermined time after counting the first predetermined time or after successful authentication with the power transmission device. The foreign object placement determination unit further includes the predetermined foreign object detection value when a magnitude of a power transmission current to the power transmission coil exceeds a predetermined foreign object detection threshold while the second timer circuit measures the second predetermined time. It is an electric power transmission system which detects that metal foreign objects other than the said power receiving apparatus were mounted in this mounting surface.

  According to this configuration, in the power transmission system, when the magnitude of the power transmission current to the power transmission coil exceeds the predetermined foreign object detection threshold while the second timer circuit measures the second predetermined time, Since it is considered that the impedance in the power transmission device has decreased, it is possible to detect that a metal foreign object other than the power receiving device is placed on the placement surface.

  In one embodiment of the present invention, the foreign object placement determining unit transmits power to the power transmission coil from when the second timer circuit measures the second predetermined time until a predetermined grace period elapses. When the current exceeds the foreign object detection threshold, it is detected that a metallic foreign object other than the power receiving device is placed on the predetermined placement surface, and the power transmission current control unit detects that the metallic foreign object is the predetermined placement surface. When the foreign object placement determining unit determines that the object is placed on the placement surface, the second timer circuit intermittently calculates the second predetermined time from the continuous power transmission current. This is a power transmission system that switches to a different transmission current.

  According to this configuration, in the power transmission system, the power transmission device causes the power transmission current to the power transmission coil from the time when the second timer circuit measures the second predetermined time until the predetermined grace period elapses to set the foreign object detection threshold value. In the case of exceeding, it is considered that the state where the impedance in the power transmission device is lowered is continued, so that it is possible to detect with high accuracy that the metal foreign object other than the power receiving device is placed on the placement surface. . Further, when the power transmission device determines that the metal foreign object has been placed on the predetermined placement surface, the power transmission device intermittently starts from the continuous power transmission current after the second timer circuit measures the second predetermined time. Therefore, the increase in power consumption can be suppressed.

  While various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  The present invention relates to a power receiving device and a power receiving device that, when approaching a power transmission device, increase a change in impedance in the power transmission device by flowing a constant current over a certain period of time, and recognize that the power receiving device is mounted on the mounting surface. It is useful as a method and power transmission system.

10 Power Transmission Device 11 Control CPU
12, 25 Power supply IC
13 Drive circuit 14 Inverter circuit 15 LPF
16 On-Board Detection Circuits 17, 21 Resonant Capacitor 18 Foreign Object Detection Circuit 20 Power Receiving Device 22 Rectification Smoothing Circuit 23 DC / DC
24 Charger 26 Constant current circuit I Transmission current Ith1 Constant current operation threshold RxC Power reception coils TM1, TM2 Timer circuit TxC Power transmission coil

Claims (15)

A power receiving coil for receiving a non-contact power from the power transmission device,
A first timer circuit for measuring a first predetermined time when an induced voltage corresponding to the intermittent transmission power received by the power receiving coil exceeds a predetermined value according to an intermittent transmission current in the power transmission device ;
While the first timer circuit measures the first predetermined time , a predetermined constant current flows so as to reduce the impedance of the power transmission device in accordance with an operation control signal from the first timer circuit . A constant current circuit that stops constant current operation so that the impedance of the power transmission device increases when a predetermined time elapses ,
Power receiving device. A power receiving coil for receiving power from a power transmission device in a contactless manner;
A power receiving device comprising: a rectifying / smoothing circuit that performs rectification processing and smoothing processing on a power signal received by the power receiving coil;
The power receiving device is:
Based on the output from the rectifying and smoothing circuit, charging the rechargeable battery with the power transmitted from the power transmitting device, or operating the system of the power receiving device;
A first timer circuit for measuring a first predetermined time when an induced voltage corresponding to the intermittent transmission power received by the power receiving coil exceeds a predetermined value according to an intermittent transmission current in the power transmission device;
While being branched from the power supply line from the rectifying / smoothing circuit to the charging unit and disposed between the rectifying / smoothing circuit and the grounding unit of the power receiving apparatus, the first timer circuit measures the first predetermined time. A constant current circuit through which a predetermined constant current flows according to an operation control signal from the first timer circuit,
Power receiving device. The power receiving device according to claim 1 or 2 ,
After the first timer circuit starts measuring the first predetermined time, based on a transmission signal in which a predetermined authentication signal is superimposed on a power signal corresponding to a continuous transmission current based on the predetermined constant current An authentication unit that authenticates with the power transmission device,
Power receiving device. The power receiving device according to claim 3 ,
A DC transformer that transforms an induced voltage corresponding to the power received by the power receiving coil into a predetermined DC voltage;
A second timer circuit for measuring a second predetermined time after the first predetermined time is measured or after successful authentication with the power transmission device,
While the second timer circuit measures the second predetermined time, the power receiving coil and the direct current transformer are non-conductive.
Power receiving device. The power receiving device according to claim 3 ,
A DC transformer that transforms the induced voltage into a predetermined DC voltage;
A second timer circuit for measuring a second predetermined time after counting the first predetermined time or after successful authentication with the power transmission device;
A charge control unit for charging the rechargeable battery based on the power received by the power receiving coil; and
The charge controller is
After the second timer circuit has timed the second predetermined time, based on the electric power continuously transmitted from the power transmission device, through the DC transformer unit that has become conductive with the power receiving coil, Charging the rechargeable battery,
Power receiving device. A power receiving method in a power receiving device,
Receiving the intermittent transmission power corresponding to the intermittent transmission current in the power receiving coil from the power transmission device in a contactless manner;
A step of measuring a first predetermined time in a first timer circuit when an induced voltage corresponding to the intermittent transmission power received by the power receiving coil exceeds a predetermined value;
While the first timer circuit measures the first predetermined time, a predetermined constant current flows in the constant current circuit so as to reduce the impedance of the power transmission device according to an operation control signal from the first timer circuit. Steps,
Stopping the operation of the constant current circuit so as to increase the impedance of the power transmission device after the first predetermined time has elapsed ,
Power receiving method. A power receiving method in a power receiving device,
Receiving the intermittent transmission power corresponding to the intermittent transmission current in the power receiving coil from the power transmission device in a contactless manner;
Performing a rectification process and a smoothing process on a power signal received by the power reception coil in a rectification smoothing circuit;
Charging a rechargeable battery with electric power transmitted from the power transmission device based on an output from the rectifying and smoothing circuit in a charging unit, or operating a system of the power reception device,
The power receiving method is:
Measuring a first predetermined time in a first timer circuit when an induced voltage corresponding to the intermittent transmission power received by the power receiving coil exceeds a predetermined value according to an intermittent transmission current in the power transmission device; ,
In the constant current circuit that is branched from the power supply line from the rectifying / smoothing circuit to the charging unit and disposed between the rectifying / smoothing circuit and the grounding unit of the power receiving device, the first timer circuit includes the first predetermined circuit. A step of causing a predetermined constant current to flow in response to an operation control signal from the first timer circuit while measuring time.
Power receiving method. A power transmission system including a power transmission device and a power reception device,
The power transmission device is:
A power transmission coil for non-contact power transmission according to intermittent power transmission current;
A placement detector that detects that the power receiving device is placed on a predetermined placement surface;
The power receiving device is:
A power receiving coil for receiving the power transmitted from the power transmitting coil;
A first timer circuit that counts a first predetermined time when an induced voltage corresponding to the power received by the power receiving coil exceeds a predetermined value;
A constant current circuit through which a predetermined constant current flows in response to an operation control signal from the first timer circuit while the first timer circuit measures the first predetermined time;
The above-mentioned position detector is
Detecting that the power receiving device is mounted on the predetermined mounting surface in response to a change in impedance in the power transmitting device based on the predetermined constant current;
Power transmission system. The power transmission system according to claim 8 ,
The power transmission device is:
After the placement detector detects that the power receiving device is placed on the predetermined placement surface, the power signal corresponding to the continuous transmission current based on the predetermined constant current is set to a predetermined value. Transmitting a transmission signal superimposed with an authentication signal from the power transmission coil,
The power receiving device is:
An authentication unit that authenticates with the power transmission device based on the transmission signal transmitted from the power transmission coil after the first timer circuit starts measuring the first predetermined time;
Power transmission system. The power transmission system according to claim 9 ,
The power receiving device is:
A DC transformer that transforms the induced voltage into a predetermined DC voltage;
A second timer circuit for measuring a second predetermined time after counting the first predetermined time or after successful authentication with the power transmission device;
A charge control unit for charging the rechargeable battery based on the power received by the power receiving coil; and
The power transmission device is:
After the second predetermined time has elapsed, power based on continuous power transmission current is transmitted from the power transmission coil in a contactless manner,
The charge controller is
After the second timer circuit measures the second predetermined time, the rechargeable battery is connected to the rechargeable battery via the direct current transformer that is electrically connected to the power receiving coil based on the power transmitted from the power transmitting coil. To charge,
Power transmission system. The power transmission system according to claim 9 ,
The power transmission device is:
A foreign object that detects that a metal foreign object other than the power receiving device is placed on the predetermined placement surface based on the magnitude of the power transmission current to the power transmission coil and the success or failure of authentication with the power receiving device. A placement determination unit;
A power transmission current control unit configured to increase an output period of the intermittent power transmission current over a predetermined period after the foreign material placement determination unit determines that the metal foreign matter is placed on the predetermined placement surface; , Further comprising
Power transmission system. The power transmission system according to claim 11 ,
The transmission current controller is
When the authentication between the power transmission device and the power reception device fails in the predetermined period, the output cycle of the intermittent power transmission current is decreased.
Power transmission system. The power transmission system according to claim 11 ,
The transmission current controller is
When the transmission current after the output cycle has increased is less than a predetermined foreign object detection threshold, the output cycle of the intermittent transmission current is decreased,
Power transmission system. The power transmission system according to claim 11 ,
The power receiving device is:
A second timer circuit for measuring a second predetermined time after counting the first predetermined time or after successful authentication with the power transmission device,
The foreign object placement determination unit includes:
A metal other than the power receiving device on the predetermined placement surface when the magnitude of the power transmission current to the power transmission coil exceeds the predetermined foreign object detection threshold while the second timer circuit measures the second predetermined time. Detect that a foreign object has been placed,
Power transmission system. The power transmission system according to claim 14 ,
The foreign object placement determination unit includes:
When the second timer circuit finishes counting the second predetermined time and the power transmission current to the power transmission coil after the predetermined grace period elapses exceeds the foreign object detection threshold, the predetermined placement Detecting that a metal foreign object other than the power receiving device is placed on the surface,
The transmission current controller is
When the foreign matter placement determination unit determines that the metallic foreign matter has been placed on the predetermined placement surface, the second timer circuit counts the second predetermined time. Switching from a normal transmission current to the intermittent transmission current,
Power transmission system.

Images